The present invention relates to improvement in a sleeve for an anchor bolt used on concrete or light-weight concrete.
FIG. 1 shows a conventional sleeve for an anchor bolt which is formed with a partially threaded through hole 1 and a plurality of axial slits 2. After the sleeve has been put in a hole in concrete, a separate wedge 3 is driven into the sleeve in the direction of arrow to spread open the slitted end of the sleeve, thereby ensuring that the sleeve is fastened in concrete. With the conventional sleeve, the wedge was made separately from the sleeve body to a suitable size for the hole in the body. This increases the manufacturing cost and entails much labor. Further, the pairs each consisting of a body and a wedge are liable to be disturbed because the wedge often gets lost. A correct wedge has to be driven into a sleeve body. Another problem is that since the wedge is a separate member, it might become loose from the slitted end as it is subjected to vibration. This decreases the anchoring effect of the anchor bolt.